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Establishment of a novel approach for evaluation of interaction between the implanted vascular device and its surrounding tissues

Subasinghe, Sandeepani Kanchana

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Cite this item:
Subasinghe, S. K. (2016). Establishment of a novel approach for evaluation of interaction between the implanted vascular device and its surrounding tissues (Thesis, Master of Science). University of Otago. Retrieved from http://hdl.handle.net/10523/6462

Introduction: When evaluating the reactions of an implanted vascular stent to its surrounding tissue, histopathological studies and different imaging techniques have made an invaluable contribution. However, there are a number of practical drawbacks in presently practicing methods. The aim of the present study was to develop a novel ultrathin sheet plastination technology for evaluation of the interaction of the implanted vascular device and its surrounding structures.

Materials methods: The study was performed on 18 plastinated arteries of a sheep from which 2 were harvested at 3 weeks and the remaining flow diverter stents were harvested at 6 months post deployment. The geometry patterns of the implanted stents were visualized through micro-CT and followed by sectioning into ultrathin sections (150-200µm) and staining using different staining methods. The configuration of the arterial wall and the stent strut were analyzed using the ordinary, stereo– and confocal microscopy.

Results: The geometry pattern and architecture of the implanted flow diverter stents in the plastinated block were depicted by micro-CT scans. Macroscopic and microscopic features of the vascular wall were revealed on the same slice, which allowed in evaluation of most of the currently practicing evaluation criteria. It was noted that single geometry pattern of a device elicited different vascular reactions throughout its length. The interface between the implanted device and its surrounding soft tissue were well preserved. It was evident that the alternation of the vessel wall following the implantation process resulted in device guided neointimal formation that lead to the occlusion of the implanted vessel. The flow diverter stents used in the present project had blocked the perforating branches, which was not the ideal condition.

Conclusion: The technique described in this study had four unique features: (1) maintains the in situ condition of the implanted stent and vascular wall architecture, (2) preserves the fine configuration of the interface between the stent and the vascular wall, (3) enable the currently used macro- / microscopic evaluation criteria to be examined on the same sections and 4) has the ability to correlated the 3D geometry of the implanted device with its corresponding 2D serial sections. The flow diverters used in present study has not illustrated optimal characteristics due to it device guided neointimal formation resulting in occlusion of the targeted vessel and its associated branching arteries. Therefore, the devices used in the present study have failed to show optimal characteristics, which in turn not suitable for clinical application.